Reversible refrigerating apparatus for heating and cooling



Feb. 21, 1939. J. M. LABBERTON REVERSIBLE REFRIGERATING APPARATUS FORHEATING AND COOLING Original Filed July 13, 1933 2 SheetsSh e-st l \J M2 mm H r -mwm J S mm 3 o MN 5 x J v \l s ,1 m ullil l hm a 1. L W U .3 3S W \N .ll *m m vm m mm\ m. 2 q n 2 mm hm mm 3 v 1 MN H W 2 2 2 w hm m mm m INVENTOR JOHN M. Lassen-TON WITNESSES:

BY .621. W

ATTORN'EY' Feb. 21 1939. J, M. LABBEETON 7 2,148,415

REVERSIBLE REFRIGERATING APPARATUS FOR HEATING AND COOLING OriginalFiled July 13, 1933 2 Sheets-Sheet 2 In In WITNESSES: INVENTOR 7? TJOHNM.LRBBERTON BY GI Q W ATTORNEY Patented Feb. 21, 1939 PATENT OFFICES Q REVERSIBLE REFRIGERATING APPARATUS FOR HEATING D COOLING John M.Labberton,

Pittsburgh, Pa., assignor to Westinghouse Electric & ManufacturingCompany, East Pittsburgh, Pa., a corporation of Pennsylvania ApplicationJuly 13, 1933, Serial No. 680,307

Renewed January 15, 1936 25 Claims.

My invention relates to reversible refrigerating apparatus for heatingand cooling, that is, compression refrigerating apparatus operating onthe compression refrigeration cycle for cooling and operating on thereverse refrigeration cycle for heating, and it has for an object toprovide an improved system of apparatus of this character.

It is a further object to provide an improved piping arrangement forsaid apparatus.

Another object is to provide a system in which the lubricant entrainedin the refrigerant is returned to the compressor and not accumulated inthe evaporator.

A further object is to provide improved control means for reversiblerefrigerating apparatus.

In accordance with my invention, I provide two heat exchangers adaptedto function alternatively as condenser and evaporator, respectively, andvice versa. These heat exchangers are of the type providing dryevaporation when functioning as evaporators. Each heat exchanger isprovided with an inlet adjacent to the uppermost level of the heatexchanger and with an outlet near the lowermost level. The discharge ofthe compressor is connected to the inlet of each heat exchanger and itssuction is connected to the outlet of each heat exchanger. Other conduitmeans are provided to convey condensed refrigerant from the outlet endof each heat exchanger to the inlet end of the other heat exchanger.

I also provide control means embodying one thermostat for controllingthe cooling action and a second thermostat for controlling the heatingaction. A control device, such as a two-way switch, is provided forrendering either one of the thermostats operative, so that the apparatuscan function only for cooling or only for heating in accordance with thefunction-for which the valves are set. I may also provide mechanismwhereby the control device also effects adjustment of the valves for thefunction corresponding to the thermostat which is rendered operative.

The above and other objects are effected by my invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawings, forming a part of this application inwhich:

Fig. 1 is a diagrammatic view of apparatus embodying my invention;

Fig. 2 is a vertical sectional view showing the upper portion of one ofthe heat exchangers in greater detail;

Fig. 3 shows a modification of a detail;

Fig. 4 is a diagrammatic view of apparatus having a greater degree ofautomatic control; and

Fig. 5 is a detail view of a modified form of valve-control mechanism.

Referring now to the drawings more in detail,

I show at In a portion of a room of a house which is to be cooled whenthe temperature therein is higher than desired, as in the summer, andwhich is to be heated when the temperature is lower than desired, as inthe winter. The apparatus includes two heat exchangers H and I2, shownin perspective in Fig. 1, the former being arranged in anysuitablemanner known in the art in heat exchange relation with the interior ofthe room III. For simplicity of illustration, I have shown it asdisposed within the room "L. The heat exchanger I2 is arranged in heatexchange relation with a region exterior to the room III, for example,it may be placed outdoors in direct contact with the outside atmosphere.

Each heat exchanger includes a plurality of pipes or coils I3 eachhaving horizontal legs l4 and having its inlet end adjacent theuppermost level of the heat exchanger and its outlet end adjacent thelowermost level of the heat exchanger. Each heat exchanger includes anupper horizontal header Hi, to which the inlet end of each coil I3 isconnected by means of an inverted T-shaped fitting l6' which extendsdownwardly from the header l5, as shown more clearly in Fig. 2. Thestructure of Fig. 2 is the same as the structure of Fig. 1; except thatFig.

2 shows fins H which are preferably provided on 5 the coil l3 for thepurpose of increasing the heatexchanging surface of the coil. TheT-shaped fitting also has an inlet I8 for liquid refrigerant, as will behereinafter described. The header I5 is providedat one end with a vaporinlet IS. The outlet or lower ends of the coils l3 are directlyconnected to a lower header 20 which has a vapor outlet 2| and a liquidoutlet 22.

The apparatusfurther includes a compressor 23 and a motor 24 driving thecompressor. The compressor and motor may be disposed in the basementII). A discharge conduit 25 communicates with the discharge or outlet ofthe compressor and has two branch conduits 26 and 21 communicating withthe vapor inlets heat exchangers II and I2, respectively. The branchconduits 26 and 2! are provided with valves 28 and 28 respectively,disposed adjacent the common discharge conduit 25. A return or suctionconduit 28 communicates with the suc- 55 IQ of the provides flow tion orinlet of the compressor and has two branch conduits 29 and IIcommunicating with the vapor outlets 2! of the heat exchangers II andI2, respectively. An oil-separator 50 is interposed in the conduit 28,and the oil separated therein is conveyed to the crank case of thecompressor through a conduit 5!. Valves 32 and 32' are provided in thebranch conduits 25 and II, respectively, adjacent the vapor outlets 2|.

A liquid conduit 33 communicates with the liquid outlet 22 of the heatexchanger ii for conveying liquid refrigerant from the heat exchanger IIto the heat exchanger l2 when the former is acting as a condenser for,heating the room II. The conduit 33 has a liquid receiver 33'interposed therein and communicates with the heat exchanger l2 throughsuitable expansion valve means for reducing the pressure of the liquidrefrigerant. Such expansion valve means may be any means known in theart which of refrigerant from the high pressure portion of the system tothe low pressure portion but which restricts such flow so as to preventequalization of pressures in the two portions of the system. I prefer,however, for the present purpose, to use flow resistance passages of thetype known in. the art as capillary tubes. Accordingly, I show capillarytubes 34 extendin between the conduit 33 and the liquid inlet l5 of eachcoil l3 of the heat exchanger l2. In order to restrict the admission ofliquid refrigerant to the evaporator l2 to the amount that can beevaporated, particularly in cold weather, I provide a valve 35 in theconduit 33. The valve 35 may also be used to supplement the capillarytubes 34 in expanding or reducing the pressure of the refrigerant.Thevalve 35 is operated by a control mechanism 36 which includes abellows 31 into which the pressure in the header I5 is introducedthrough a conduit 33 and a second bellows 39 communicating with athermostatic tube 4l, the latter being placed adjacent to the suctionconduit 3|. A spring 40 biases the valve 35 toward closed position. Thetension of the spring 40 may be adjusted by an adjusting nut 40.

The pressure in the bellows 31 is a function of the saturationtemperature of the liquid refrigerant in the evaporator 12 and thepressure in the bellows 39 is a function of the temperature of thevaporized refrigerant exhausted from heat exchanger I2. The differenceof these pressures is, therefore, a measure of the degree of superheatof the exhausted refrigerant, and by controlling the admission of liquidrefrigerant to maintain substantially a predetermined degree ofsuperheat, the return of unvaporized liquid refrigerant to thecompressor is avoided. Control mechanisms of this type are known in theart.

There is also interposed in the conduit 33 a valve 42 for the purpose ofshutting oif all flow through the conduit when thecompressor is shutdown and when the heat exchanger 12 operates as a condenser. The valve42 is biased to closed position by a spring 43, and is adapted to beopened by. an electro-magnet 44, which is controlled as hereinafterdescribed.

A liquid conduit 45 is connected to the liquid outlet 22 of the heatexchanger l2 for conveying liquid refrigerant to the heat exchanger II.when the latter is operating as an evaporator, as in the summer. Theconduit 45 also has, a liquid receiver 45' interposed therein andcommunicates with the coils l3 of the heat exchanger I I throughsuitable expansion valve means, preferably cap- -ductor 58, and theother,

iilary tubes 34 connected to the liquid inlets l8, similarly to the heatexchanger l2. A hand-set valve 45 is provided in'the conduit 45 adjacentthe capillary tubes 34 for supplementing the controlling or expandingaction of the capillary tubes, whereby said controlling or expandingaction may be varied. The conduit 45 is also provided with a valve 41which is biased to closed position by a spring and adapted to be openedby a magnet 49.

The control mechanism for the apparatus includes a thermostat 5| forsummer operation, adapted to close a pair of electrical contacts 52 inresponse to a predetermined maximum temperature within the room l0, anda thermostat 5|" for winter operation, adapted to close a pair ofcontacts 53 in response to a predetermined minimum temperature withinthe room i0. One contact of each of the pairs of contacts 52 and 53 isconnected through a conductor 54, which includes the winding of a relay56, to one line conductor 55.

A two-blade, double-throw switch 51, when in the right hand positiondesignated S, connects the other contact 52 to the line conductor 55,and when in the left hand position designated W, connects the othercontact 53 to the line conductor 55.

One terminal of each of the electro-magnets 44 and 48 is connected tothe line conductor 55. The switch 51, when in the position S, connectsthe other terminal ofthe electro-magnet 49 to the line conductor 55, andwhen in the position W, connects the other terminal of the electromagnet44 to the lineconductor 55, in each case through the contacts of therelay 55. One terminal of the motor 24 is connected to the lineconthrough the contacts of the relay 55, to the line conductor 55. It isto be understood that conventional motor starting means may be employed.

The operation of the above described apparatus is as follows:

For summer operation, room 10, the valves 28 and 32 are opened, thevalves 28" and 32" are closed, and the switch 51 is thrown to the righthand position S. Upon the temperature in the room in exceeding apredetermined value, the thermostat 5l closes its contacts 52 toenergize the relay 56, closing its contacts. The latter energizes theelectro-magnet 49, opening the valve 41, and also starts the motor 24.The apparatus operates in the usual manner of compression refrigeratingapparatus, the heat exchanger l2 functioning as a condenser and the heatexchanger ll functioning as an evaporator to cool the room ID.

The refrigerant compressed by the compressor 23 is conveyed through theconduit 25, the valve 28 and the branch conduit 21 to the vapor inlet 19of the heat exchanger l2 and is condensed in the coils l3. The condensedrefrigerant is discharged through the liquid outlet 22 to the conduit45. From the latter it passes through the valves 41 and 45, through thecapillary tubes 34 and through the liquid inlets [8 to the upper ends ofthe coils I3 in the heat exchanger H. In the latter, the liquidrefrigerant absorbs heat from the air of the room i0 and is evaporated.

The refrigerant flows downwardly through the coils l3, so that theentrained lubricant is carried along with the vaporized refrigerant,which is returned to the compressor through the vapor outlet 2|, theconduits 29 and 23, the valve 32 and the oil separator 50.

that is cooling of the When the temperature in the room ID has beensufliciently lowered, the thermostat 5| opens the contacts 52,deenergizing the relay 5B. The motor an d compressor are stopped, andthe valve 41 is closed, thereby preventing further flow of liquidrefrigerant into the heat exchanger I I, now the evaporator. It will benoted that the contacts 53 of the thermostat 5| are cut out of circuitbythe switch 51 so that a low temperature in .the room III will notcause operation while the apparatus is set for cooling operation.

When it is desired to set the apparatus for heating operation, as in thewinter, the valves 28 and 32 are closed, the valves 28 and 32 areopened. and the switch 51 is thrown to the left-hand position W. As thetemperature in the room I decreases to a predetermined minimumtemperature, the thermostat closes the contacts 53. The contacts of therelay 56 close, opening the valve 42 and starting the motor andcompressor.

Vaporous refrigerant is compressed by the compressor 23, its temperaturebeing thereby raised, as is well known in the art. It is conveyedthrough the conduit 25, the valve 28 and the conduit 26 and admittedthrough the vapor inlet l9 to the heat exchanger ll acting as acondenser. In flowing through the heat exchanger I l, the warmcompressed refrigerant supplies heat through the coils I3 to the air inthe room I0, and is thereby condensed. It is discharged through theliquid outlet 22 and conveyed through the conduit 33, the valves 42 and35, and the capillary tubes 34, to the liquid inlets l8. of the heatexchanger l2. The pressure of the refrigerant being reduced in thelatter, it vaporizes, absorbing heat from the surrounding medium, inthis case the outdoor air. The vaporized refrigerant, having now ahigher heat content, is returned through.the conduit 3|, the valve 32'',the oil separator 60 and the conduit 28 to the inlet or suction of thecompressor.

In passing through the compressor, small quantities of lubricant areentrained in the refrigerant. The lubricant is readily carried withtherefrigerant as long as the latter is in liquid form, but begins toseparate therefrom when the refrigi erant is evaporated. In the abovedescribed apparatus, the vaporizing refrigerant flows downwardly in bothheat exchangers, so that the lubricant is readily carried along. This isalso facilitated by the fact that the exchangers are of the typeproviding dry evaporation; that is, this type has long narrow passagesproviding forced circulation of the refrigerant which helps to carry thelubricant along. The expression "dry expansion is to be taken asreferring to the type of evaporator commonly known by that name in theart, as distinguished from an evaporator of the flooded type, withoutreference to its accuracy in describing the actual condition of therefrigerant therein.

It will also be noted that the liquid refrigerant admitted through theconnections 3 is at a level below the header l5, so that the severalquant1- ties delivered by the several capillary tubes 34 to therespective coils I 3 are maintained separate.

The communication between the upper ends ofing and valve arrangement,requiring only four valves to be operated to change from heating tocooling operation, and vice versa. The valves 42 and 41 areautomatically operated.

In place of the magnetically operated valves 42 and 41 of Fig. 1, checkvalves 62, as shown in Fig. 3 may be substituted. In this case, also,the op eration is automatic. The higher pressure in the heat-exchangerfunctioning as the condenser automatically closes the check valve 52 ofthat liquid supply conduit, 33 or 45, which communicates with the liquidinlets l8 of said heat exchanger. The check valve 62 in the other liquidsupply conduit automatically opens to permit flow of liquid refrigerantfrom the heat exchanger acting as the condenser to the heat exchangerfunctioning as the evaporator.

The apparatus shown in Fig. 4 embodies control mechanism having agreater degree of automatic operation; the refrigerating apparatusproper being the same as in Fig. 1.

In this embodiment, the valves '28 28 32 and 32 are automaticallyadjusted by the switch 51' for cooling operation when the latterconnects the cooling control thermostat 5| into service and for heatingoperation when the switch 51' connects the heating control thermostat 5Iinto service. The valves 28 28", 32 and 32 are provided with solenoids63 64 65 and 66" for opening the respective valves and solenoids 53 64*,65 and 56 for closing the respective valves. One terminal of each of thesolenoids 53 54 55 and 66 is connected through conductors 61 to acontact 68 of the switch 51., which contact is connected to the lineconductor 58 when the switch is set in the summer or coolingpositionindicated at S. One terminal of each of the solenoids 63 64 65and 66 is connected through conductors 69 to a contact ll which isconnected through line conductor 58 when the switch is set in the winteror heating position W. The other terminal of each solenoid is connectedto the line conductor 55 through conductors 12.

The magnets 49 and 44 are adapted to be connected to the line conductor58 through the switch 51 and conductors 61 and 69, respectively, inthecooling and heating positions, respectively. Both magnets are connectedto the line conductor 55 through the contacts of the relay 5G.

The operation of the control mechanism of 4 to a predetermined maximumtemperature, the I relay 56 starts the motor 24 and energizes the magnet49, opening the valve 41. The apparatus now operates to cool the room IDin the manner described in connection with Fig. 1. As the temperature inthe room I0 is decreased to a desired value, the contacts 52 arereopened and cooling operation ceases.

When theswitch 51' is thrown to the left or winter position, thesolenoids 63 54 65 and 66" are energized opening the valves 28 and 32and closing the valves 28 and 32 thereby setting the same for heatingoperation. In this position of the switch 57', the thermostat 5" isconnected into service and closes its contacts 53 in response to apredetermined minimum temperature in the room III. The relay energizesthe magnet 44 to open the valve 42 and starts the motor 24. Theapparatusnow operates to heat the room as described in connection with Fig. 1until the contacts 53 are reopened as a desired temperature is attained.

In Fig. 5, I show a motor driven form of operating mechanism for thevalves 63 to 66. This form is preferably employed in the embodiment ofFig. 4 in which operating mechanism for these valves is onlyschematically shown in order to simplify and clarify illustration of thesystem. A split field motor 13 drives a worm I4 meshing with a two partfrictional drive gear- 15. The gear 15 comprises an outer part 16carrying the gear teeth and an inner part 11, which frictionally engagesthe outer part and is fixed to a rotatable shaft 18 that opens andcloses the valve. The frictional engagement is sufficient to transmitthe driving force to operate the valve until it is fully opened orclosed, when slipping between the inner and outer parts takes place.

The inner and outer parts of the gear I have two pairs of cooperatingcontacts interposed in the conductors 61 and 69, said contacts beingarranged to open the circuit to the motor, when the desired movement ofthe valve is completed.

nism shown in Fig. 5 is as follows: In the position shown on thedrawings, the conductor 61 is connected by the switch 51" to the lineconductor 58 but it is open-circuited at the gear wheel contacts, whilethe gear contacts of the conductor 69 are closed. If the switch 51" isnow thrown to the left, a circuit is completed from line conductor 58through contact H of the switch 51", conductor 69 including its contactson the gear, one field winding and the armature of the motor andconductor 12, to the line conductor 55. The motor operates to rotate thegear in counterclockwise direction to operate the valve connected to theshaft 18. The valves 28" and 32" are opened and valves 28 and 32 areclosed as described in connection with Fig. 4. When the actuation of thevalve is completed the shaft 18 and the inner part of the gear are heldagainst further movement. The outer part of the gear continues until thecontacts of the conductor 69 the switch is thrown to are moved out ofengagement, opening the circuit and stopping the motor. The continuedmovement of the outer gearpart brings the contacts of the conductor 61into contact, so that when the right, the circuit through the conductor61 is completed and the gear is rotated to the right. The valve is nowactuated in the ppposite direction until it reaches the end of itstravel, when the continued movement of the outer gear part moves thecontacts of the conductor 61 out of contact, the contacts of theconductor 69 being meanwhile brought into registry. In thisconstruction, it will be seen that the electric current is cut off whenvalve 60 actuation is completed.

From the above description, it will be seen that I have providedimproved apparatus for heating in winter and cooling in summer and whichaccomplishes the objects hereinbefore set forth.

while I have shown my invention in several forms, it will.be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and modifications, without-departing fromthesplrit thereof, and I de sire, therefore, that only such limitationsshall be placed thereupon as are imposed by the prior art or as arespecifically set forth in the appended claims.

What I claim is:

1. In reversible refrigerating apparatus for The operation of the valveoperating mechaheating and cooling, a heat exchanger adapted to functioneither as a condenser or as an evaporator of the dry expansion type andcomprising a plurality of refrigerant passa es extending from an upperlevel to a lower leve means for supplying vaporous refrigerant to thepassages adjacent the upper level when the heat exchanger is operatingas a condenser, means for admitting separate quantities of liquidrefrigerant to the respective passages adjacent the upper level when theheat exchanger is operating as an evaporator, means for maintaining saidquantities of liquid refrigerant separate adjacent the upper level, andmeans adjacent said lower level for discharging vaporous and liquidrefrigerant.

2. In reversible refrigerating apparatus for heating and cooling, a heatexchanger adapted to function either as a condenser or as an evaporatorof the dry expansion type and comprising a plurality of refrigerantpassages extending from an upper level to a lower level, a vapor inletcommunicating with said passages adjacent said upper level, means foradmitting liquid refrigerant, whenthe heat exchanger is op rating as anevaporator, individually to the respective passages at points adjacentto but below the level of communication between the several passages,and outlet means adjacent said lower level.

' 3. In reversible refrigerating apparatus for heating and cooling, aheat exchanger adapted to function either as a condenser or as anevaporator and comprising an upper header having an inlet for receivingrefrigerant vapor when the tor of the dry expansion type and having aninlet adjacent its uppermost level for receiving com-.

pressed vaporous refrigerant when functioning as a condenser, a secondinlet, for receiving liquid refrigerant when operating as an evaporator,disposed adjacent the uppermost level but below the first inlet so thatthe liquid refrigerant will not flow out through the first inlet, and anoutlet adjacent the lowermost level of the heat exchanger.

5. In reversible refrigerating apparatus for heating and cooling, thecombination of a compressor, a first and a second heat exchanger eachhaving an inlet end and an outlet end, means for conveying compressedrefrigerant from the compressor selectively to said inlet end of eitherthe first or the second heat exchanger, means for conveying expandedrefrigerant selectively from said outlet end of either the first or thesecond heat exchanger to the compressor, means for conveying refrigerantfrom said outlet end of each heat exchanger to said inlet end of theother, and means for shutting off commimication through one of thelast-mentioned means.

6. In reversible refrigerating apparatus for heating and cooling, thecombination of a compressor,'a first and a second heat exchanger eachhaving an inlet end and an outlet end, means for conveying compressedrefrigerant from the compressor selectively to said inlet end of eitherthe first or the second heat exchanger, means for conveying expandedrefrigerant selectively from said outlet end of either the first or thesecond heat exchanger to the compressor, means for conveying refrigerantfrom said outlet end of each heat exchanger to said inlet end of theother, and expansion valve and shut-off valve means in each of thelast-mentioned conveying means.

7; Reversible refrigerating apparatus for heating and cooling comprisinga compressor, a first and a second heat exchanger both of the dryexpansion type and having an inlet end and an outlet end, means forconveying compressed refrigerant from the compressor selectively to saidinlet end of either the first or the second heat exchanger, means forconveying refrigerant from said outlet end of each heat exchanger tosaid inlet end of the other, means for shutting off flow through one ofthe last-mentioned means, and means'ffor conveying evaporatedrefrigerant'selectively, from said outlet end of either the first or .7the second heat exchanger to the compressor.-

8. Reversible refrigerating apparatus for heating and cooling comprisinga compressor, a first and .a second heat exchanger both of the dry typeand having an inlet end and an outlet end, means for conveyingcompressed refrigerant from the compressor selectively to said inlet endof either the first or the second heat exchanger, means for conveyingrefrigerant from said outlet end of each heat exchanger to said inletend of the other and for expanding the same, and means for conveyingevaporated refrigerant selectively from said outlet end of either thefirst or the second heat exchanger to the compressor.

9. Reversible refrigerating apparatus for heating and cooling comprisinga compressor, a first and a second heat exchanger both of the dryexpansion type and having-an inlet end and an outlet end, means forconveying compressed refrigerant from the compressor selectively to saidin-- let end of either the first or the second heat exchanger, means forconveying refrigerant from said outlet end of each heat exchanger tosaid inlet end of the other and for expanding the same, means forshutting off flow through one of the last-mentioned means, and means forconveying evaporated refrigerant selectively from said outlet end ofeither the first or the second heat exchanger to the compressor.

10. Reversible refrigerating apparatus for heating and coolingcomprising a compressor, a first and a second heat exchanger each of thedry\type and having an inlet end adjacent its uppermost level and anoutlet end adjacentits lowermost level, means for conveying compressedrefrigerant from the compressor to said inlet end of either heatexchaiger, in which it is condensed, means for conveying condensedrefrigerant from said outlet end of each heat exi changer to said inletend of the other heat exchanger, in which it is evaporated, and meansfor conveying evaporated refrigerant selectively from said outlet end ofeither heat exchanger to the suction inlet of the compressor.

11. Reversible refrigerating apparatus for heating and coolingcomprising a compressor, a first and a second heat exchanger both ofgthedry type and having a refrigerant passage extending from an upper levelto a lower level, means, for conveying, compressed refrigerant from thecompressor selectively to' the upper end of the passage in either heatexchanger, means for conveying condensed refrigerantfrom the lower endof the passage in each heat expassage extending from an upper level to alower level, means for conveying compressed refrigerant from thecompressor selectively to the upper end of the passage in either heatexchanger, means for conveying condensed refrigerant from the lowerendof the passage in each heat exchanger to the upper end of the passagein the other heat exchanger, expansion valve means for each of thelast-mentioned means, and means for conveying evaporated refrigerantselectively. from the lower end of the passage in either heat exchangerto the suction inlet of the compressor.

13. Reversible refrigerating apparatus for heating and coolingcomprising a compressor, a first and a second heat exchanger each havingrefrigerant passages extending from an upper level to a, lower level,conduit means communicating with the discharge of the compressor andhaving branch conduits communicating with the upper ends of the passagesin the first and the second heat exchanger, respectively, valve means ineach ofsaid branch conduits, conduit means communicating with thesuction inlet of the compressor and having branch conduits communicatingwith the lower ends of the passages in the first and -the second heatexchanger, re-

spectively, valve means in each of said branch tion with the substanceto be heated or cooled,

means for conveying compressed refrigerant from the compressor to eitherheat exchanger, in which it is condensed, then to the other heatexchanger, in which it is evaporated, and back to the compressor, meansresponsive to a predetermined minimum temperature of said substance foreffecting operation of the compressor, means responsive to apredetermined maximum refrigerating apparatus for temperature of saidsubstance forv effecting operation of the compressor, and means forselectively rendering either one of the two last-named meansoperativeand the other inoperative.

15. In reversible refrigerating apparatus for heatingand cooling asubstance, the combination of a compressor, a first and a second heatexchanger adapted to function as evaporator and I condenser,respectively, or vice versa, the first heat exchanger being inheat-exchanging relation with the substance to be heated or cooled,means for conveying compressed refrigerant from the compressor to eitherheat exchanger, in which it is condensed, then to the other heatexchanger, in which it is evaporated, and back to the compressor, afirst and a second valve for shutting off supply of liquid refrigerant.to the first and to the second heat exchanger, ,respectively, meansresponsive to a predetermined maximum temperature of said substance foreffecting operation of the compressor and for opening the first valve,and means responsive to a predetermined minimum temperature foreffecting operation of the compressor and for opening the second valve.

16. The combination defined in claim 15, and further comprising meansfor selectively rendering either one of the two last-named meansoperative and the other inoperative.

17. In reversible refrigerating apparatus for heating and cooling asubstance, the combination of a compressor, a first and a second heatexchanger adapted to function as evaporator and condenser, respectively,or vice versa, the first heat exchanger being in heat exchangingrelation with the substance to be heated or cooled, means for conveyingcompressed refrigerant from the compressor to either heat exchanger inwhich it is condensed, to the other heat exchanger in which it isevaporated, and back to the compressor, means responsive to apredetermined maximum temperature of said substance for closing a firstpair of electrical contacts to start operation of the compressor,

. means responsive to a predetermined minimum temperature of saidsubstance for closing a second pair of electrical contacts to startoperation of the compressor, a first and a second magnetically-openedbias-closed valve for shutting oil supply of liquid refrigerant to thefirst and to the second heat exchanger, respectively, and a double-throwswitch adapted in one position to render the first-mentioned temperatureresponsive means and the first magnetically-opened valve operable, andin the second position to render the second-mentioned temperatureresponsive means and the second magneticallyopened valve operable.

18. In reversible refrigerating apparatus for heating and cooling asubstance, the combination of a compressor, a first and second heatexchanger adapted to function as evaporator and condenser, respectively,or vice versa, the first heat exchanger being in heat exchange relationwith the substance to be heated or cooled, conduit and valve means forconveying compressed refrigerant from the compressor selectively toeither heat exchanger, in which it is condensed, then to the other heatexchanger in which it is evaporated, and back to the compressor, meansresponsive to a predetermined minimum temperature of said substance foreffecting operation of the compressor, means responsive to apredetermined maximum temperature of said substance for effectingoperation of the compressor, and a control mechanism which is adapted inone condition to render the minimum temperature'responsivemeansoperative and the maximum temperature responsive means inoperative andto effect adjustment of the valve means for heating operation of theapparatus, and which" is adapted in a second condition to render themaximum temperature responsive means operative and the minimumtemperature responsive means inoperative and to effect adjustment of thevalve means for cooling operation of the apparatus.

19. In a reversible refrigerating apparatus for heating and cooling asubstance, the combination of a compressor, a first and second heatexchanger adapted to function as evaporator and condenser, respectively,or vice versa, the first heat exchanger being in heat exchangingrelation with the substance to be heated or cooled,

conduit and valve means for conveying compressed refrigerant from thecompressor selectively to either heat exchanger, in which it iscondensed, means for conveying liquid refrigerant from either heatexchanger to the other, a first and a second valve associated with thelast mentioned means and for shutting off supply of liquid refrigerantto the first and to the second heat exchanger, respectively, conduit andvalve means for conveying evaporated refriger ant selectively fromeither heat exchanger to the compressor, means responsive to apredetermined maximum temperature of said substance for effectingoperation of the compressor and for opening the first valve, and meansresponsive to a predetermined minimum temperature for effectingoperation of the compressor and for opening the second valve, and acontrol mechanism which is adapted in one condition to render themaximum temperature responsive means operative and. the minimumtemperature responsive means inoperative and to effect adjustment of thevalve means for, cooling operation of the reversible refrigeratingapparatus, and which is adapted in a second position to render theminimum temperature responsive means operative and the maximumtemperature responsive means inoperative and to effect adjustment of thevalve means for heating operation of the reversible refrigeratingapparatus.

20. Reversible refrigerating apparatus for heating and coolingcomprising a compressor, a first and a second heat exchanger adapted tofunction as evaporator and condenser, respectively, or vice versa, thefirst heat exchanger being in heat-exchanging relation with thesubstance to be heated or cooled, control means adapted to be placed ina first condition for effecting heating operation and in a secondcondition for effecting cooling operation, and means operative when thecontrol means is in said first condition to provide for fiow ofrefrigerant from the compressor to the first heat exchanger, in which itis condensed, then to the second heat exchanger, in which it isevaporated, and back to the compressor, and operative when the controlmeans is in said second condition to provide for flow of refrigerantfrom the compressor to the second heat exchanger, in which it iscondensed, then to the first heat exchanger, in which it is evaporated,and back to the compressor.

21. Reversible refrigerating apparatus for heating and coolingcomprising a compressor, a first and a second heat exchanger, saidsecond heat exchanger being of the dry type and havin a refrigerantpassage extending from an upper level to a lower level, means forconveying comveying evaporated refrigerant selectively from the firstheat exchanger or from the lower end of the passage in the second heatexchanger to the suction inlet of the compressor.

22. Reversible refrigerating apparatus for heating and coolingcomprising a compressor, a first and a second heat exchanger adapted tofunction as evaporator and condenser, respectively, or vice versa, thefirst heat exchmer being in heat-exchanging relation with the substanceto be heated or cooled, control means adapted to be placed in a firstcondition for effecting heating operation and in a second condition foreffecting cooling operation, means responsive to a predeterminedminimumtemperature for controlling heating operation of the compressor, andmeans responsive to a predetermined maximum temperature for controllingcooling operation of the compressor.

23. Reversible refrigerating apparatus for heating and coolingcomprising a compressor, a first and a second heat exchanger adapted tofunction as condenser and evaporator, respectively, and vice versa, thefirsteheat exchanger being in heat exchanging relation with thesubstance to be heated or cooled, and means for selectively conditioningthe apparatus for fiow of refrigerant from the compressor to the firstheat exchanger in which it is condensed, then to the second heatexchanger, in which it is evaporated, and back to the compressor, toprovide heating operation of the apparatus and for controlling saidheating operation in response to a predetermined minimum temperature, orconditioning the apparatus for fiow of refrigerant from the compressorto the second heat exchanger, in which it is condensed, then to thefirst heat exchanger, in which it is evaporated, and back to thecompressor, to provide cooling operation of the apparatus and forcontrolling said cooling operation in response to a predeterminedmaximum temperature.

24. In reversible refrigerating apparatus for heating and cooling asubstance, the combination of a compressor, a motor for driving thecompressor, a first and a second heat exchanger adapted to function ascondenser and evaporator,

respectively, or vice versa, the first heat exchanger being in heatexchange relation with 'the substance to .be heated or cooled, conduitand valve means for selectively conveying compressed refrigerant fromthe compressor to the first heat exchanger in which it is condensed,then to the second heat exchanger in which it is evaporated,

and back to the compressor, for heating operation,

or conveying compressed refrigerant from the compressor to the secondheat exchanger in which it is condensed, then to the first heatexchanger, in which it is evaporated, and back to the compressor, forcooling operation, electrically energized means for actuating said valvemeans, electrical circuits for said last-mentioned means and for saidmotor, and means for controlling said circuits and electricallyenergized means for selectively actuating said valve means to provideflow of refrigerant for heating operation or actuating said valve meansto provide fiow of refrigerant for cooling operation.

25. In reversible refrigerating. apparatus for heating and cooling asubstance, the combination of a compressor; a motor for driving thecompressor; a first and a second heat exchanger adapted to function ascondenser and evaporator, respectively, or vice versa, the first heatexchanger being in heat exchange relation with the substance to beheated or cooled; conduit and valve means for selectively conveyingcompressed refrigerant from the compressor to the first heat exchangerin which it is condensed, then to the second heat exchanger in which itis evaporated, and back to the compressor, for heating operation, orconveying compressed refrigerant from the compressor to :the second heatexchanger in which it is condensed, then to the first heat exchanger, inwhich it is evaporated, and back to the compressor, for coolingoperation; electrically energized means for actuating said valve means;electrical circuits for said last-mentioned means and for said motor;means for controlling said circuits and electrically energized means forselectively actuating said valve means to provide flow of refrigerantfor heating operation or actuating said valve means .to provide fiow ofrefrigerant for cooling operation; means responsive to a predeterminedminimum temperature for controlling operation of the apparatus when thevalve means is actuated to provide flow of refrigerant for heatingoperation; and means responsive to a predetermined maximum temperaturefor controlling operation of the apparatus when the valve means

